Endothelin, having potent vasoconstrictive effect and blood pressure elevating effect, is considered to be a substance that contributes to various diseases and disorders including heart diseases such as ischemic heart infarction, congestive heart failure, arrhythmia, and unstable angina; airway diseases such as asthma; hypertonia such as pulmonary hypertension and renal hypertension; hypofunctions of organs which may occur in association with operation or transplantation thereof; circulatory diseases such as subarachnoid hemorrhage, post-PTCA reconstriction, and vasospasm; kidney diseases such as acute and chronic renal failure; diabetes, hyperlipemia, and other diseases that are accompanied by vascular lesion; arteriosclerosis; liver diseases such as alcohol-induced liver disorders; gastrointestinal disorders such as those of gastric mucosa; bone diseases; prostatic hypertrophy; and urinary disorders; cancer Saishin-Igaku (may be translated to "Medicine Up-to-date"), 94, 335-431 (1994), Igaku-no-Ayumi (may be translated to "Progress of Medicine"), 168, 675-692 (1994), Igaku-no-Ayumi, 170, 357 (1994)!.
It has come to be elucidated that a variety of actions of endothelin are triggered upon binding of endothelin to its receptors in organs of the body, and that the vasoconstriction caused by endothelin is induced by the mediation of at least two different receptors (ET.sub.A and ET.sub.B receptors). Therefore, a compound that prevents endothelin from binding to these two receptors should be useful as a preventive and therapeutic agent for the above-mentioned diseases in which endothelin participates. Heretofore, a number of compounds have been reported as exhibiting endothelin antagonism J. Med. Chem., 36, 2585 (1993), Nature, 365, 759 (1993), Circulation, 88, 1-316 (1994), Saishin-Igaku, 94, 424-431 (1994), J. Med. Chem. 37, 1553 (1994), and Japanese Patent Application Laid-Open (kokai) Nos. 5-222003, 6-211810, 7-17972, and 8-99961)!.
However, no compound has yet been found to exhibit satisfactory endothelin antagonism.
Accordingly, the present invention is directed to the discovery of a compound that has potent endothelin antagonism, as well as to the provision of pharmaceuticals containing such a compound as the active ingredient.